Piezoelectric sensors are used in many applications to sense mechanical loads or movement, including vibration. One example of the use of piezoelectric sensors is in a bed for accommodating a patient in a health care facility or home care setting. The sensors may be used to reveal patient position and/or movement. The sensors may also be used to measure patient weight or to monitor physiological variables such as patient respiration and heart rate.
When used in such applications, piezoelectric sensors are integrated into a mattress or otherwise installed where they are both between and in contact with other components of the bed. As a result, the sensors may sustain damage causing them to malfunction. As a result, any information based on the sensor could be erroneous. It is, therefore, desirable to be able to assess the status of the sensors so that malfunctioning sensors can be identified and appropriate corrective action can be taken if necessary.